In a service delivery environment through public networks centered around the Internet, values of all information are generally concentrated on a server side rather than a client side.
In other words, each client (terminal device) is basically a mere viewer browsing information on the Internet. Each client issues requests for various information to the Internet, which in return may obtain such information from the client. It means that all information is collected on the Internet and it only offers formulaic information unidirectionally. For this reason, it is difficult for manufacturers of client terminal devices to create an added value.
In order to change such a circumstance, the server-client relationship must be reversed by inverting the access direction. That is, when there is a home network connected to the Internet, it is necessary to create an environment for allowing the Internet to access the home network to receive a service therefrom.
To achieve this, each apparatus connected to the local network must be uniquely identifiable from the Internet, and intra-home routing and security problems must be solved. One of the technologies for addressing this issue is the IPv6 (Internet Protocol version 6).
However, considering the environment surrounding the current carriers and Internet service providers in Japan, it may take considerably longer before IPv6 becomes widespread. For example, the currently used IPv4 machines need at least 2 to 3 years for their depreciation and IPv6 service is offered on a test basis only.
In order to immediately provide an IPv6-enabled network, manufacturers must expand their business to ISP level services, which is very costly and unrealistic for most of them. Since existing home networks vary broadly in their structures and also in connection mechanisms depending on the carrier and ISP, there is a need for a mechanism for absorbing all these differences to achieve the IPv6 environment with a standardized approach.
In the conventional IPv4 environment, the following problems arise in an attempt to achieve such bidirectional accesses as would be possible in IPv6 networks between the home network and the Internet.
For example, when installing network home appliances at home in the current IPv4 environment, each of the appliances should be connected to a router connected to the Internet through the home network. Accordingly, an IP address of the respective network home appliance becomes a private address and cannot be accessed from non-home network.
Thus an access to the network home appliances has been conventionally achieved by employing a dedicated router capable of controlling the network home appliances, or by first accumulating information for controlling the network home appliances at a data center provided on the Internet and then retrieving the information by performing polling from the network home appliances.
However, such a dedicated router compromises the system's versatility and increases the cost. Also when retrieving the control information by polling, real time accesses cannot be made and the network and server load increases.
In order to overcome these challenges, a network connection method and a relay device were disclosed by the present assignee in International Application No. PCT/JP2005/9280 (Publication No. WO2005/114926), filed on May 20, 2005, the disclosure of which is incorporated herein by reference. The present invention enables bidirectional communication between the home network and the Internet by relatively simple means by establishing a tunneling connection session between a computer system in a private network and an InterServer on the Internet.
Particularly, one or more of the relay devices disclosed in the Publication No. WO2005/114926 are installed as one or more programs in the client apparatus and each has an interface recognized as a virtual device driver. Such a structure may allow the communication described above with relatively simple configuration. However, the technique disclosed in the above publication communicates via an OS (operating system) installed in the client apparatus and does not allow communication by applications using a protocol whose protocol stack does not exist in the OS.
For example, under an OS with no IPv6 protocol available, it may not be possible to use applications which communicate with IPv6.
Considering the above situation, the purpose of the present invention is to provide a communication module for enabling applications to use a particular communication protocol thereby to perform bidirectional communication utilizing a virtual network without relying on a particular network environment such as an OS.